<?php
class HtmlUtil {
	protected static $htmlTags = array(
        'allow' => 'table|td|th|tr|i|b|u|strong|img|p|br|div|strong|em|ul|ol|li|dl|dd|dt|a',
        'ban' => 'html|head|meta|link|base|basefont|body|bgsound|title|style|script|form|iframe|frame|frameset|applet|id|ilayer|layer|name|script|style|xml',
    );
	
	private function __construct() {
		throw new CatException('Can not construct!');
	}
	
	/**
	 * 用于sql的like语句，%、_有特殊含义
	 */
	public static function forSqlLike($string) {
        return str_replace( array('%','_'), array('\%','\_'), $string );
    }
	
	/**
	 * 文本在textarea中显示用它处理
	 */
	public static function forTarea($string) {
        return preg_replace(array('/<(textarea)>/i','/<\/(textarea)>/i'), array('&lt;$1>','&lt;/$1>'), $string);
    }
	
	/**
	 * 文本在input中显示（一般是value值）用它处理
	 */
	public static function forInput($string) {
        return str_replace(array('"',"'"), array('&quot;','&#039;'), $string);
    }
	
	/**
	 * 希望html以源码形式显示用它处理
	 */
	public static function forShow($string) {
		return nl2br(preg_replace(array("/&amp;/i", "/&(nbsp);/i"), array('&', '&amp;$1;'), htmlspecialchars($string, ENT_QUOTES)));
    }
	
	/**
	 * 过滤危险html代码（主要是一些脚本）
	 */
	public static function xssClean($data) { 
		// Fix &entity\n; 
		$data = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $data); 
		$data = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $data); 
		$data = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $data); 
		$data = html_entity_decode($data, ENT_COMPAT, 'UTF-8'); 
		 
		// Remove any attribute starting with "on" or xmlns 
		$data = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $data); 
		 
		// Remove javascript: and vbscript: protocols 
		$data = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $data); 
		$data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*v[\x00-\x20]*b[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2novbscript...', $data); 
		$data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $data); 
		 
		// Only works in IE: <span style="width: expression(alert('Ping!'));"></span> 
		$data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#i', '$1>', $data); 
		$data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#i', '$1>', $data); 
		$data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:*[^>]*+>#iu', '$1>', $data); 
		 
		// Remove namespaced elements (we do not need them) 
		$data = preg_replace('#</*\w+:\w[^>]*+>#i', '', $data); 
		 
		do 
		{ 
			// Remove really unwanted tags 
			$old_data = $data; 
			$data = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $data); 
		} 
		while ($old_data !== $data); 
		 
		// we are done... 
		return $data;
	}
	
	/**
	 * 删除html，得到纯文本
	 */
	public static function clearHtml($string, $allowTags = '') {
		return strip_tags($string, $allowTags);
    }
	
	/**
	 * 嵌入flash文件，使用swfobject.js
	 * http://code.google.com/p/swfobject
	 */
	public static function flash() {
		
	}
}
?>